Cache management in a composite data environment

ABSTRACT

Techniques and a system are provided for a cache manager system. The cache manager system includes features allowing the content selection system to determine when to use information stored in a cache memory or when to request a refresh of profile information by executing a merge of information from two or more data sources.

TECHNICAL FIELD

The present disclosure relates to data processing using databases and,more specifically, to reducing time, memory, and other computingresources by creating and maintaining identifiers from composite datasources. SUGGESTED GROUP ART UNIT: 2161; SUGGESTED CLASSIFICATION: 707.

BACKGROUND

Computers allow humans access to information in large quantities, withgreater ease than before. Even for data sources that were “siloed” orkept separate, computers help to break down walls separating these datasources. These different data sources may be created, maintained, ormodified by different companies or organizations, but sometimesdifferent data sources exist even within a single company ororganization.

The ease of producing vast amounts of data from various data sourcesoutstrips our ability to make sense of and use the data. Data from eachdata source is usually stored in different forms, meaning that theinformation from each source may be encoded using different formats,have different digital identifiers for the same or similar pieces ofinformation, or include other differences. This makes it difficult tounderstand how information from one data source relates to another pieceof information from another data source.

As one example, it is useful to be able to properly select content for aperson so that it matches their taste. However, each person's digitallife has gotten much more complicated. A person may have informationspread across multiple data sources, for example, browsing historystored with one service, purchase history with another, socialnetworking profile including their friends and family, news servicesthey visit, and communications platforms they use to reach out toothers. Each of these data sources is an important, but incompletepicture of the person. For example, a social networking site mayindicate who a person knows and communicates with, but will generallylack information on what the person's viewing history is. As anotherexample, a news service may indicate news preferences of a user, butwill not have information with whom the user shares news articles with.

It is often computationally expensive to merge all these data sourcestogether. For example, the processing power to scour data from each datasource and then to reconcile data from the data sources is difficult andtime-consuming. To reduce these computationally expensive operations,merging is avoided or done infrequently, resulting in information thatis stale and of reduced usefulness.

Therefore, there is a need to reach a balance between computationallyexpensive operations and having up-to-date information.

The approaches described in this section are approaches that could bepursued, but not necessarily approaches that have been previouslyconceived or pursued. Therefore, unless otherwise indicated, it shouldnot be assumed that any of the approaches described in this sectionqualify as prior art merely by virtue of their inclusion in thissection.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 illustrates a content selection system, according to anembodiment.

FIG. 2 shows an example flow of how a request is processed by variouscomponents of the content selection system.

FIG. 3 is a flowchart that depicts an example process for generatingprofiles.

FIG. 4 is a flowchart that depicts an example process for determiningwhether to use profiles stored in a cache.

FIG. 5 is a block diagram that illustrates a computer system upon whichan embodiment of the invention may be implemented.

DETAILED DESCRIPTION

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of the present invention. It will be apparent, however,that the present invention may be practiced without these specificdetails. In other instances, well-known structures and devices are shownin block diagram form in order to avoid unnecessarily obscuring thepresent invention.

General Overview

A content selection system is described herein which implementstechniques for determining, from various pieces of available content,whether to transmit content to a user and selecting what content totransmit to the user. The content selection system may be used withvarious types of content. As an example, content items may includedifferent types (e.g., application, audio, image, message, model,multipart, text, video, or any combination of these) and for differentpurposes (e.g., entertainment, advertisement, education, or otherpurposes).

The content selection system may use other systems, such as a profilemanager system or a cache manager system. In various embodiments, thecontent selection system may include both the profile manager system andthe cache manager system, or the profile manager system, depending onthe specific needs of the content selection system.

The profile manager system includes features to create profiles ofentities. These profiles are used by the content selection system tomatch entities to content for which the entities would be best suitable.The profile manager system allows the content selection system toidentify different pieces of data from different data sources and matchthe different pieces of data when the pieces of data refer to the sameentity. The profile manager system may also provide merging of thedifferent pieces of data, when they are matched as referring to the sameentity. The profile manager system does the merging “lazily,” meaningthat the merging is done on-demand according to a specified event. Forexample, the profile manager system may execute a merge when a requestfor content or other specified event occurs.

In an embodiment, a request occurs when a user requests information froma remote computing device. The requests may come from the user'scomputing device via various means. For example, the user may be usingan application, a web browser, a background application, or any othermethod to request information remotely. In an embodiment, a requestcomes from a Web browser for a Web page. The Web page includes a portionon the Web page where content is required. For a single Web page, theremay be multiple portions requiring content and, for each portionrequiring content, a separate request is made. For example, a Web pagemay include more than one advertisement and for each advertisement, aseparate request is made.

When performing a merge, the profile manager system identifies adominant identifier corresponding to an entity that made a request, suchas a user entity that has requested a Web page. The dominant identifiermay be any identifier that maps to other identifiers used by the datasources, including an identifier that is already used by a data source.For example, a social networking identifier may be used as both thedominant identifier as well as the identifier for the data source fromthe social network. In an embodiment, the dominant identifier isselected to be a long-lasting identifier. The long-lasting identifier isan identifier that is unlikely to expire or change. Some examples oflong lasting identifiers include account log on information, emailaddresses, and others. Some examples of non-long lasting identifiersincluded in the content selection system 100 include IP addresses,mobile device identifiers, and others.

When the dominant identifier is identified, the profile manager systemperforms a lookup to determine what additional identifiers correspond tothe dominant identifier. These additional identifiers correspond toidentifiers used by one or more data sources to identify the same entityrepresented by the dominant identifier. The profile manager system thencombines information from the data sources to create a profile for theentity.

In various embodiments, the profile manager system may execute mergeswhen various criteria are met. For example, merging may be done when aretargeting event has been received. As discussed in greater detailelsewhere, a retargeting event may be when the profile manager systemreceives an opt-out request, a language change request, or many othertypes of events. Merging may also be done when a certain time period haselapsed. For example, the profile manager system may include a timeperiod, where the time period specifies a length of time beforepreviously created profiles becomes stale. When the time period haselapsed, the profile manager system may execute a merge to generateupdated profile information.

The cache manager system includes features allowing the contentselection system to determine when to use information stored in a cachememory or when to request a refresh of profile information by executinga merge of information from two or more data sources. Response time isoften a limiting factor when responding to a request. Some examples ofwhere there is a low latency requirement includes advertising onreal-time bidding advertisement exchanges. On these exchanges, anadvertisement request should be completed in less than 100 milliseconds,hence, the expected time budget for the profile manager may be as low as5 milliseconds. If a response to the request occurs after this time,then the request may no longer be usable.

When profile information is requested for an entity, the cache managersystem performs a cache lookup, to determine whether there is profileinformation for the entity and, if there is profile information, whetherthe profile information may be used. As an example, even if there existsprofile information on an entity, the cache manager system may determineto use or not use the profile information if the profile information isstale (e.g., time when the profile information was generated hasexceeded a predetermined amount of time, signifying that the informationis likely inaccurate or of low value).

If the profile information is not to be used, then the profile managerdetermines how to respond to the request. The cache manager system mayattempt to generate the profile information in response to the request(e.g., using the profile manager system). However, if the time requiredto generate the profile information exceeds a certain amount of time,the profile manager returns whatever incomplete data that could befetched for the given time, and then asynchronously fetches thefull/complete profile to be used for subsequent requests.

Sample Use Case: Advertising Content Selection

In an embodiment, the content selection system 100 is used to selectadvertisements. Advertisement targeting data comes from various datasources. Some of it comes from data sources managed by the sameorganization executing the content selection system 100. For example, ifthe organization is a social networking Website, such as LINKEDIN, thenthere are different data stores available to use to select the bestadvertisement for users. An example are data stores used for memberprofiles (including information such as skills, companies, etc.). Someinformation may come from data stores of partners, some may come fromdata stores with purchased information, or some information derivedinformation from any of these data stores (e.g., through the use of dataanalytics). Each of these data stores use an identifier to identify auser. However, the identifiers used for the same user may be differentacross the data stores. Hence, bits and pieces of targeting data iscollected using different identifiers (such as LINKEDIN memberidentifier, mobile device identifier, browser identifier, emailaddresses, phone numbers, hashed email address, and other identifiers).To create a complete profile to target content for a user, theinformation collected from different identifiers should be mergedtogether. Some examples that may trigger a merge are:

(1) Data associated with one of identifiers is updated.

(2) Relationship between identifiers change. New identifiers may bediscovered for a user (they login via a new device for instance), orexisting IDs may expire or be deleted.

Given the large number of users and potential requests for content fromusers there are two approaches that may be used:

(1) Offline data merge, where mapping identifiers and merging is limitedto certain times. Offline data merge is slow to run. Hence, the profilesgenerated during the offline data merge can be generated a few times aday, which would not be fresh enough for retargeting scenarios. Anotherlimitation of offline merge is handling of multi-version derived data,in which merged data should be created for all permutations of allversions. As a result, storage of the merged data would not be scalable.In the derived data scenario, this may mean that a first algorithm usedto generate derived data from machine learning techniques generates afirst version of information and a second algorithm generates a secondversion of information, even though the first and second algorithms arebased off the same data sets. Alternatively, a single algorithm maygenerate different versions of derived data, by changing assumptionsused to generate the derived data. For example, suppose the algorithmcalculates values to determine whether various thresholds are met usinga mix of information from one or more data sources as well as constantvalues. By adjusting the constant values, additional versions of deriveddata may be produced, even though the same algorithm and data sourcesare used.

Different versions of data may result in a rapid increase in datastorage needed to generate, compare, and use the data. For instance,assume there are seven total data stores, five data stores that providedata in a single version, one data store that has two versions of itsdata, and another data store that has three versions of its data. Thetotal number of possible profiles generated using all of the data storeswould then be six (2 times 3). To properly test an algorithm using ABtesting, all these profiles would need to be created and stored. Thismeans that it is possible to quickly run out of memory in one or morecomputing devices used to store the information, just by generating theprofiles. As a result, more computing devices would be needed to storethe merged data, which would increase the cost of finding and matchingcontent items, and the system could not scale as the number of datasources and versions of information created from the data sourcesincrease.

(2) Stream processing, where a stream of events is received by a nearreal-time system and, in response, the merged targeting data isgenerated. These events do not necessarily correspond to requests madeby users and may be any piece of information newly received by thesystem. The downside of this approach is the rate of events is high andtriggers many merges that may not even be used. This would be waste ofprocessing power and increase the cost of serving such data.Additionally, similar to offline-merge approach, this approach also haslimitations in handling the multi-version stores, and may requireproducing merged data for all combinations of data versions.

To serve relevant content to users, many data sources with differentuser information are collected, inferred, or even purchased. Forinstance, LINKEDIN's advertising serving system may use profile data,various segment info (internal or advertiser-defined), fuzzy searches(including such things as synonyms, singular/plural forms, possiblemisspellings, stemmings, related searches, and other relevantvariations), and derived data to show relevant content. In general,different advertising targeting data may be keyed by different useridentifiers (e.g., login identifier, mobile ID, browser ID, emailaddresses, phone numbers, or partner IDs), and the relationship betweenIDs may evolve (e.g., ownership of a phone number may change, users mayopt-out of a partners' network, a user changes her mobile device, etc.).

The profile manager component 102 learns what identifiers are used for auser across the different data stores. The raw data in these data storesare keyed by their original identifier in each respective data store anda merge is executed lazily based on users' content item requests. Whenan ad request comes, the profile manager component 102 looks upidentifiers related to a user associated with the ad request and fetchestargeting data associated with the user from different stores. Mergedtargeting data may be cached for subsequent access.

In an embodiment, the cache does not include targeting information forall of the users represented in the data stores. The content selectionsystem 100 limits the size of the cache, but keeping only a certainnumber of targeting information or keeping only targeting informationfor a certain period of time before it is removed. This allows thecontent selection system 100 to reduce the necessary size of the cache.

Example Content Selection System

FIG. 1 illustrates a content selection system 100 in which thetechniques described may be practiced according to certain embodiments.The content selection system 100 is a computer-based system. The variouscomponents of the content selection system 100 are implemented at leastpartially by hardware at one or more computing devices, such as one ormore hardware processors executing instructions stored in one or morememories for performing various functions described herein. For example,descriptions of various components (or modules) as described in thisapplication may be interpreted by one of skill in the art as providingpseudocode, an informal high-level description of one or more computerstructures. The descriptions of the components may be converted intosoftware code, including code executable by an electronic processor. Thecontent selection system 100 illustrates only one of many possiblearrangements of components configured to perform the functionalitydescribed herein. Other arrangements may include fewer or differentcomponents, and the division of work between the components may varydepending on the arrangement.

The content selection system 100 includes various components used toselect content. For ease of understanding, these components are brokeninto different groups: a profile manager component 102, a cache managercomponent 104, a data stores component 106, a publisher component 108,and a content provider component 109. Each component group may have oneor more additional components as part of the group. However, alternateembodiments of the content selection system 100 may include more orfewer components in each component group, as well as component groupingsdifferent than the one shown in FIG. 1.

Although the content selection system 100 shows both the profile managercomponent 102 and the cache manager component 104, various embodimentsof the content selection system 100 may include only the profile managercomponent 102.

The profile manager component 102 is responsible for creating, updating,and managing profiles for entities stored in the system. In anembodiment, the profile manager component 102 is used with data onpersons, such as Internet users. However, various embodiments mayinclude other types of entities such as groups, organizations, or othertypes. An identification recognition component 110 is responsible fordetermining, based on a particular piece of data from the data storescomponent 106, to which user the particular piece of data refers.

A dominant identifier lookup component 111 is responsible fordetermining, based on the user identified by the identificationrecognition component 110, a corresponding dominant identifier for theuser. For example, the identification recognition component 110 hasdetermined that a first piece of data corresponds to a first userbecause of a first identifier in the first piece of data. The dominantidentifier lookup component 111 performs a lookup using the firstidentifier to determine what the corresponding dominant identifier isfor the first identifier. The dominant identifier may be the same ordifferent than the first identifier.

In an embodiment where profiles of the profile manager component 102 areInternet users, the identification recognition component 110 receives afirst piece of information on the Internet user. For example, this maybe Web browsing information of the Internet user on a social networkingWebsite and the identification recognition component 110 determines auser account name is included with the Web browsing information. Usingthe user account name, the dominant identifier lookup component 111translates this information to a dominant identifier used by the profilemanager component 102.

A profile generator component 112 is responsible for merging pieces ofinformation in the data stores component 106 to create a profile. Forexample, after the dominant identifier lookup component 111 hasdetermined a dominant identifier for a piece of information, the profilegenerator component 112 may retrieve an existing profile associated withthe dominant identifier. The existing profile may need to be updatedwith pieces of information, from one or more data stores. Areconciliation component 114 is responsible for working with the profilegenerator component 112 to determine how a piece of information isincorporated with an existing profile if there is a conflict betweenpieces of information from data stores and the existing profile. Thereconciliation component 114 may replace, update, or supplement alreadyexisting information from the piece of information with the existingprofile. For example, if an existing profile already indicates a user isinterested in cars and the piece of information indicates the user isinterested in travel, then the reconciliation component 114 maydetermine the updated profile may include both cars and travel asinterests or replace cars with travel.

A machine learning component 116 is responsible for improving resultsdetermined by the content selection system 100. The content selectionsystem 100 may employ various types of testing methods to determine theaccuracy of the profiles created by the profile manager component 102.For example, the profile manager assumes that, if the profiles arehighly accurate for users, then the likelihood of users approving,viewing, or interacting with content selected based on the profiles willincrease. Different testing techniques may be used to determine andcompare the increased likelihood. Some of these testing techniquesinclude AB testing, click-through testing, successful conversiontesting, and many other types of testing. The machine learning component116 may work in conjunction with the content provider component 109.

An information removal component 117 is responsible for removingprofiles or information from profiles, based on specific events. Asdiscussed in greater detail elsewhere, there may be a variety of reasonswhy, for a profile that has already been generated and stored (e.g., incache storage) may need to be updated.

The cache manager component 104 is responsible for retrieving profileswhen a request received. As discussed in greater detail elsewhere, thecontent selection system 100 provides more than one method to supply aprofile, depending on various factors.

The data stores component 106 includes various data sources accessibleby the profile manager component 102 to generate profiles. Each datasource is associated with a reliability or query time indicator. Forexample, different data sources may have different response times. Somedata sources may have a very low response time (e.g., load on the datasource is low, data source is hosted on fast computing equipment, datasource is an internal data source, data source prioritizes requests fromthe profile manager, or other reasons) when compared to others. Asdiscussed in greater detail elsewhere, this assists the cache managercomponent 104 to determine whether a request may be satisfied.

Each data source is associated with a reliability or query timeindicator. For example, different data sources may have differentresponse times. Some data sources may have a very low response time(e.g., load on the data source is low, data source is hosted on fastcomputing equipment, data source is an internal data source, data sourceprioritizes requests from the profile manager, or other reasons) whencompared to others. As discussed in greater detail elsewhere, thisassists the cache manager component 104 to determine whether a requestmay be satisfied.

Some examples of data sources include:

Internal Data Sources 118 and 120. These include data sources created,maintained, and managed by an organization that is executing the profilemanager component 102. Each data source may come from different teamsfrom within the organization, such as a team focusing on user submittedprofile information and a team focusing on user submitted connectionsinformation.

Third-Party Data Source 122. This includes data sources created,maintained, and managed by an organization different than anorganization executing the profile manager component 102. As an example,the third-party data source 122 includes data stores accessible by oneorganization from another organization through a rental or sharingagreement between the organizations.

Derived Data Source 124. This includes data sources created, maintained,and managed by an organization that were not provided by usersthemselves, but determined through analyzing pieces of information fromother data stores (e.g., internal data stores, third-party data stores,or other data stores). For example, if a user is associated with piecesof information relating to automobiles, such as online activityindicating visiting Web pages discussing automobiles or visiting Webpages of car dealerships, then the derived data source may indicate aninterest for the user in automobiles.

There are numerous ways the content selection system 100 may produce orreceive produced information for the derived data store. Derived data isusually generated using multiple machine learning algorithms, andthrough experimentation, the best algorithm is selected. Suchexperimentation is called A/B testing. An example of A/B testingincludes:

The profile manager component 102 is responsible for handing A/Btesting. For instance, suppose have we have a data provider that needsto experiment with two algorithms (algorithms 1 and 2), and has providedits data in a single store. At runtime, depending on A/B testingrequirements, the profile manager may read data generated by algorithm 1for a subset of users, and data generated by algorithm 2 for the rest ofusers. The results for profiles generated using the derived informationmay be compared, to determine whether algorithm 1 or algorithm 2produced more positive outcomes. Some examples of positive outcomes maybe increased conversion rate for content items matched using profiles,increased user interaction for content items matched using profiles,increased ease of use for content items matched using profiles, or manyother outcome types.

Five examples of different data stores are shown in the data storescomponent 106, however there may be fewer or more data stores than shownhere. For example, there may be more internal data sources than shown inFIG. 1 or no third-party data source 122. Other data stores may also beincluded, not shown in FIG. 1.

The publisher component 108 is responsible for indicating when there areopportunities for the content selection system 100 to include content.For example, the publisher component 108 notifies the content selectionsystem 100 that a user has viewed a Web page, and that there are one ormore opportunities for the content selection system 100 to includecontent.

The content provider component 109 is responsible for content in thecontent selection system. The content provider component 109 usesprofile information from the profile manager component 102 to match theuser with the most relevant content item.

Request Processing

Some specific flows for implementing a technique of an embodiment arepresented below, but it should be understood that embodiments are notlimited to the specific flows and steps presented. A flow of anotherembodiment may have additional steps (not necessarily described in thisapplication), different steps which replace some of the steps presented,fewer steps or a subset of the steps presented, or steps in a differentorder than presented, or any combination of these. Further, the steps inother embodiments may not be exactly the same as the steps presented andmay be modified or altered as appropriate for a particular applicationor based on the data.

FIG. 2 shows an example flow 200 of how a request is processed byvarious components of the content selection system 100, in anembodiment. In a first step, a request 202 is received by the contentselection system 100. The request 202 may include various pieces ofinformation, such as identifying information of an entity that made therequest, where the entity made the request, and other information. Therequest may be associated with a single user of the content selectionsystem 100. In a second step, an identifier mapping component 204determines from an identifier store 206 what identifying information isincluded with the request, a dominant identifier associated with theidentifying information, and other identifiers associated with thedominant identifier. The cache manager component 104 provides furtherprocessing of the request. In a third step, the cache manager component104 performs a cache lookup 208. For example, the cache managercomponent 104 will determine from a cache 210 if there exists a storedprofile for the dominant identifier, as well as when the stored profilewas generated. In a fourth step, a store access manager 212 willdetermine which profile, if any, is returned in response to the request.For example, the store access manager 212 may determine what data is tobe included with a request. The store access manager 212 may optionallydetermine a context and expected response time to satisfy the request.Various embodiments of the cache manager component 104 may include allor a subset of these options to reply to the request:

Cache Hit. If the store access manager 212 determines that there existsa stored profile and that the stored profile for the dominant identifieris not stale, then the store access manager 212 may return the storedprofile.

Cache Miss—Hard Cache Miss. If the store access manager 212 determinesthat there is no stored profile for the dominant identifier, then thestore access manager 212 may choose to generate a new profile. Forexample, the store access manager 212 is aware that first and seconddata sources would be required to generate the new profile. Based on anexpected response time for the first and second data sources (e.g.,historical analysis of response times), the store access manager 212determines that, although the stored profile is unusable, it would bepossible to generate the new profile and timely respond to the request.For example, the store access manager 212 determines a timeout forfetching data from a data store. If one or more data stores timeout andcannot produce their profile information before the timeout, then thestore access manager 212 will mark any profile created for the dominantidentifier as incomplete. The incomplete profile may still betransmitted for use. Additionally, the store access manager 212 mayasynchronously fetch information from the timed out data sources togenerate a complete profile. This complete profile is stored for useduring subsequent requests.

Cache Miss—Soft Cache Miss. If the store access manager 212 determinesthat the stored profile for the dominant identifier is stale, then thestore access manager 212 may choose to provide the stored profile. Thestore access manager 212 determines that it would still be valuable toprovide the stored profile in response to the request, even when theprofile is stale. After responding to the request, the store accessmanager 212 instructs the new profile to be generated, asynchronous toresponding to the request to be used for any subsequent requests.

No Response. If the store access manager 212 determines that the storedprofile for the dominant identifier is stale and that it would not bevaluable to provide the stored profile, then the store access manager212 may choose to forgo responding to the request. This may mean thatthe request will be ignored or that the content selection system 100will select content without associated profile information. Afterchoosing to forgo responding to the request, the store access manager212 may instruct a new profile to be generated, asynchronous toresponding to the request.

In a fourth step, a profile aggregator 214 provides a profile 216according to the path determined by the store access manager 212. Theprofile aggregator 214 may access the data stores component 106, asdescribed in greater detail elsewhere. This profile 216 is stored in thecache 210, for potential future use. In a fifth step, the profile isprovided in response to the request.

Removing Information from Profiles

In an embodiment, the content selection system 100 includes features toremove information from existing profiles. Removal of information isgenerally specific to the data source. Some examples of data sourcesinclude:

Expiring Data Source. A data store may be collecting a type ofinformation that expires. As an example, a Web browsing data storeincludes Web browsing history of a user. Web browsing information fromthe data store may only be kept and used for a certain period of time.Thus, if profiles include information from the Web browsing data store,then, when the certain period of time has passed, the profile must beupdated to remove information in the profile generated based on the Webbrowsing data store. An example is information collected by a webbrowser. User information collected by the web browser is tied to a webbrowser identifier. In many areas of the world, information collectedand indexed by a browser identifier is usable only for a certain lengthof time, as defined by laws in each country, state, or locality.

Opt-Out. A data store may be collecting a type of information that auser provides about themselves (e.g., through their browsing history,entry of information online, language selection, or other). However,after the user has provided the information, the user may choose toun-share or opt-out from allowing the content selection system 100 touse the information. For example, if a user has shared their locationinformation and it is stored in a location data source, they may laterdecide to no longer share their location information. Thus, if theuser's profile includes their location information, then the systemremoves this location information. In another example, a user may selecta language for content they would like to receive. However, subsequentto their selection, they decide they would no longer like to receivecontent in their selected language. Thus, if the user's profile includeslanguage information, then the content selection system 100 removes thislanguage information.

The content selection system 100 may include a listener, which monitorsspecific data stores. The monitored data stores may be those indicatedas including information that may be subject to a request for removal.When a removal request is received, the content selection system 100receives an event that contains the user identifier, and generates anupdated profile for the user to replace the previously stored profile.

Example Flow for Generating Profiles

FIG. 3 is a flowchart that depicts an example process 300 for generatingprofiles, in an embodiment. In a step 302, the content selection system100 provides content selection system 100 data stores with informationon multiple users. For example, each data store includes information onmultiple users. There is user data on at least one user in each of thedata stores. In a step 304, the content selection system 100 receives arequest for content. For example, the user with information stored inthe data stores makes a request for content. In a step 306, the contentselection system 100 determines an identifier associated with request.This may be a dominant identifier, used by the content selection system100 to index a corresponding profile for the user.

In a step 308, the content selection system 100 determines associatedidentifiers with the identifier. For example, a look up is performedusing the determined identifier in step 306, to determine what otheridentifiers there are for the determined identifier. These otheridentifiers are identifiers used by one or more data sources to holdinformation related to the determined identifier.

In a step 310, the content selection system 100 determines whether tosend content in response to the request. For example, if the contentselection system 100 determines that the profile is of low value (e.g.,stale or of otherwise low value), then the content selection system 100may determine to not send content in response to the request. In a step312, the content selection system 100 selects content to send inresponse to the request. The content may be any of the types of contentas discussed in this application.

Example Flow for Cache Management

FIG. 4 is a flowchart that depicts an example process 400 fordetermining whether to use profiles stored in a cache, in an embodiment.In a step 402, the content selection system 100 receives a request forcontent. In a step 404, the content selection system 100 determines howto handle the request. For example, the content selection system 100 mayuse the cache manager component 104 to determine which options to use inreplying to the request, as discussed in greater detail elsewhere.

In a step 406, the content selection system 100 determines whether touse profile information in the cache storage. Profile information may beany type of information useful for the content selection system 100 todetermine the best fit of content for a specific request. In anembodiment, profile information includes a profile for a user that makesa request for content. The profile is used to determine tastes,interests, propensity, or other information on the user that indicateswhat kind of content that would be best suited for the user. In a step408, the content selection system 100 determines to use information inthe cache storage and returns the cache information in response to therequest.

In a step 410, the content selection system 100 determines to not useinformation in the cache storage and determines whether to make asynchronous update. For example, a synchronous update occurs when aprofile for a user is updated and the updated profile is provided inresponse to the request.

In a step 412, the content selection system 100 determines to provide asynchronous update and determines profile information. In a step 414,the content selection system 100 provides profile information. In a step416, the content selection system 100 updates the cache with thedetermined profile information.

In a step 418, the content selection system 100 determines to notprovide a synchronous update and provides the best available profileinformation. This may include profile information already stored in thecache, even if the profile information is potentially stale. In a step420, the content selection system places in a queue an instruction toupdate the profile information. The queue may include one or moreinstructions for updates to profile information. Instructions in thequeue may be processed as a batch or when computing resources areavailable to do so. In a step 422, after content is selected by thecontent selection system 100, the content selection system determinesprofile information when the queue is processed. In a step 424, thecontent selection system 100 updates the cache with the determinedprofile information.

Example Embodiment of Managing Composite Identifiers

In an embodiment, the content selection system 100 includes data stores.Each data store includes information about one or more users. The datastores may include different types of data (e.g., Web browsinginformation, connections in a social network platform, and many others).The content selection system 100 receives a request for content topresent on a computing device. The request may come indirectly from auser through a publisher. The request includes an identifier for theuser. Identifiers may be any piece of information used to identifydifferent users. In various embodiments, the identifier is at least oneof a social network member identifier, a browser identifier, a deviceidentifier, or a third-party identifier established by a third-partythat is different than the party that receives the request.

In response to receiving the request, the content selection system 100retrieves first user data from a first data store and second user datafrom a second data store. For example, a single identifier comes withthe request. The content selection system 100 maps, based on the singleidentifier, other identifiers that one or more data stores may use toreference a user with the single identifier. This may result in one ormore identifiers for the request, such as identifiers for each datasource. The first and second user data are combined to generatecomposite user data or combined user data. Using the combined user data,the content selection system 100 determines whether to send content(and/or which content to send) to the computing device. The contentselection system 100 may also indicate to the publisher that the contentselection system 100 will transmit content and select the content to betransmitted.

The content selection system 100 may also, for a second request forcontent to present on a second computing device, made after the firstrequest, retrieve the combined user data from cache storage. In variousembodiments, the computing device and the second computing device may bethe same computing device. If the user is surfing the Internet on theircomputing device, they may make many requests for content to the contentselection system 100. For example, the user may be engaged in a browsingsession, where the user navigates from one page to the next in a singleviewing session. Alternatively, if the user is viewing a single Web pagewith a large amount of content, then the content selection system 100may receive multiple requests for content for the single Web page.

In another embodiment, the computing device and the second computingdevice are different devices. When they are different devices, thecontent selection system 100 identifies, based on the requests, that thesame user made the first and second requests. Although the combined userdata was created in response to the first request, the content selectionsystem 100 may use the combined data for the second request.

The content selection system 100 may include features to delete datastored in the data stores. As described previously, this may be inresponse to expiring data, opt-out requests, or other reasons. Thecontent selection system 100 identifies the particular data store wherethe data to be deleted is stored and then removes the data.

In an embodiment, the content selection system 100 determines that thereexists prior combined user data before receiving the request. However,because the prior combined user data has expired, contains opt-outinformation, or for other reasons, the content selection system 100determines to not use the prior user data and determines to generate newcombined user data.

Example Embodiment of Cache Management with Composite Identifiers

In an embodiment, the cache manager component 104 includes receiving arequest for content to present on a computing device, where the requestincludes an identifier. In response to receiving the request, the cachemanager component 104 determines whether user data associated with theidentifier is in cache storage. In response to the cache managercomponent 104 determining that no user data that is associated with theidentifier is stored in the cache storage, the cache manager component104 retrieves first user data from a first data store. However, thecache manager component 104 determines to not wait to retrieve, from asecond data store, second user data that is associated with theidentifier and that is stored in the second data store. This may be dueto the second data store having long response times, or any of the otherreasons as discussed elsewhere in this application. Based on the firstuser data, the cache manager component 104 determines whether to sendcontent to the computing device. This may be an incomplete user profilebecause it lacks information (e.g., from a second data store) accessibleto the cache manager component 104 but not used.

In various embodiments, the request is a first request and afterdetermining to not wait to retrieve the second user data, the cachemanager component 104 retrieves the second user data from the seconddata store. The cache manager component 104 combines the second userdata with the first user data to generate combined user data and storesthe combined user data in the cache storage. After storing the combineduser data in cache storage and after determining whether to send contentto the computing device, the cache manager component 104 receives asecond request for content to present on a second computing device. Inresponse to receiving the second request, the cache manager component104 retrieves the combined user data from the cache storage anddetermines, based on the combined user data, whether to send content tothe second computing device.

In another embodiment, where the request is a first request, the cachemanager component 104 receives a second request for content to presenton a second computing device, where the second request includes a secondidentifier and, in response to receiving the second request, determineswhether user data that is associated with the second identifier isstored in the cache storage. For example, a dominant identifier isdetermined for the second request and the cache is searched based on thedominant identifier. In response to determining that particular userdata that is associated with the second identifier is stored in thecache storage, the cache manager component 104 determines whether theparticular user data in the cache storage is classified as stale.Information may be classified as stale if the time from when it wascreated from the request exceeds a predetermined amount of time. If theparticular user data is stale, then the cache manager component 104determines, based on the particular user data, whether to send contentto the second computing device. The cache manager component 104retrieves, based on the second identifier, first particular user datafrom the first data store and second particular user data from thesecond data store. This may occur after the cache manager component 104has determined whether to transmit content. The second particular userdata is used to generate combined particular user data with the firstparticular user data.

In an embodiment, determining not to wait for the second data storeincludes determining that a threshold period of time has elapsed sincethe data request to the second data store and that no response to thedata request has yet been received from the second data store.

In an embodiment, the cache manager component 104 accesses a profiledata source and a derived data source. Other embodiments may includemultiple data sources for profile data and derived data. The profiledata source includes information provided by users about themselves. Thederived data source includes information generated based on theinformation that users provide about themselves and/or information aboutonline user behavior, such as which web pages have been visited, whichcontent has been selected, and which files have been downloaded. Forexample, derived data may indicate an interest a user has in a certaincategory.

Hardware Overview

According to one embodiment, the techniques described herein areimplemented by one or more special-purpose computing devices. Thespecial-purpose computing devices may be hard-wired to perform thetechniques, or may include digital electronic devices such as one ormore application-specific integrated circuits (ASICs) or fieldprogrammable gate arrays (FPGAs) that are persistently programmed toperform the techniques, or may include one or more general purposehardware processors programmed to perform the techniques pursuant toprogram instructions in firmware, memory, other storage, or acombination. Such special-purpose computing devices may also combinecustom hard-wired logic, ASICs, or FPGAs with custom programming toaccomplish the techniques. The special-purpose computing devices may bedesktop computer systems, portable computer systems, handheld devices,networking devices or any other device that incorporates hard-wiredand/or program logic to implement the techniques.

For example, FIG. 5 is a block diagram that illustrates a computersystem 500 upon which an embodiment of the invention may be implemented.Computer system 500 includes a bus 502 or other communication mechanismfor communicating information, and a hardware processor 504 coupled withbus 502 for processing information. Hardware processor 504 may be, forexample, a general purpose microprocessor.

Computer system 500 also includes a main memory 506, such as a randomaccess memory (RAM) or other dynamic storage device, coupled to bus 502for storing information and instructions to be executed by processor504. Main memory 506 also may be used for storing temporary variables orother intermediate information during execution of instructions to beexecuted by processor 504. Such instructions, when stored innon-transitory storage media accessible to processor 504, rendercomputer system 500 into a special-purpose machine that is customized toperform the operations specified in the instructions.

Computer system 500 further includes a read only memory (ROM) 508 orother static storage device coupled to bus 502 for storing staticinformation and instructions for processor 504. A storage device 510,such as a magnetic disk or optical disk, is provided and coupled to bus502 for storing information and instructions.

Computer system 500 may be coupled via bus 502 to a display 512, such asa cathode ray tube (CRT), for displaying information to a computer user.An input device 514, including alphanumeric and other keys, is coupledto bus 502 for communicating information and command selections toprocessor 504. Another type of user input device is cursor control 516,such as a mouse, a trackball, or cursor direction keys for communicatingdirection information and command selections to processor 504 and forcontrolling cursor movement on display 512. This input device typicallyhas two degrees of freedom in two axes, a first axis (e.g., x) and asecond axis (e.g., y), that allows the device to specify positions in aplane.

Computer system 500 may implement the techniques described herein usingcustomized hard-wired logic, one or more ASICs or FPGAs, firmware and/orprogram logic which in combination with the computer system causes orprograms computer system 500 to be a special-purpose machine. Accordingto one embodiment, the techniques herein are performed by computersystem 500 in response to processor 504 executing one or more sequencesof one or more instructions contained in main memory 506. Suchinstructions may be read into main memory 506 from another storagemedium, such as storage device 510. Execution of the sequences ofinstructions contained in main memory 506 causes processor 504 toperform the process steps described herein. In alternative embodiments,hard-wired circuitry may be used in place of or in combination withsoftware instructions.

The term “storage media” as used herein refers to any non-transitorymedia that store data and/or instructions that cause a machine tooperation in a specific fashion. Such storage media may comprisenon-volatile media and/or volatile media. Non-volatile media includes,for example, optical or magnetic disks, such as storage device 510.Volatile media includes dynamic memory, such as main memory 506. Commonforms of storage media include, for example, a floppy disk, a flexibledisk, hard disk, solid state drive, magnetic tape, or any other magneticdata storage medium, a CD-ROM, any other optical data storage medium,any physical medium with patterns of holes, a RAM, a PROM, and EPROM, aFLASH-EPROM, NVRAM, any other memory chip or cartridge.

Storage media is distinct from but may be used in conjunction withtransmission media. Transmission media participates in transferringinformation between storage media. For example, transmission mediaincludes coaxial cables, copper wire and fiber optics, including thewires that comprise bus 502. Transmission media can also take the formof acoustic or light waves, such as those generated during radio-waveand infra-red data communications.

Various forms of media may be involved in carrying one or more sequencesof one or more instructions to processor 504 for execution. For example,the instructions may initially be carried on a magnetic disk or solidstate drive of a remote computer. The remote computer can load theinstructions into its dynamic memory and send the instructions over atelephone line using a modem. A modem local to computer system 500 canreceive the data on the telephone line and use an infra-red transmitterto convert the data to an infra-red signal. An infra-red detector canreceive the data carried in the infra-red signal and appropriatecircuitry can place the data on bus 502. Bus 502 carries the data tomain memory 506, from which processor 504 retrieves and executes theinstructions. The instructions received by main memory 506 mayoptionally be stored on storage device 510 either before or afterexecution by processor 504.

Computer system 500 also includes a communication interface 518 coupledto bus 502. Communication interface 518 provides a two-way datacommunication coupling to a network link 520 that is connected to alocal network 522. For example, communication interface 518 may be anintegrated services digital network (ISDN) card, cable modem, satellitemodem, or a modem to provide a data communication connection to acorresponding type of telephone line. As another example, communicationinterface 518 may be a local area network (LAN) card to provide a datacommunication connection to a compatible LAN. Wireless links may also beimplemented. In any such implementation, communication interface 518sends and receives electrical, electromagnetic or optical signals thatcarry digital data streams representing various types of information.

Network link 520 typically provides data communication through one ormore networks to other data devices. For example, network link 520 mayprovide a connection through local network 522 to a host computer 524 orto data equipment operated by an Internet Service Provider (ISP) 526.ISP 526 in turn provides data communication services through the worldwide packet data communication network now commonly referred to as the“Internet” 528. Local network 522 and Internet 528 both use electrical,electromagnetic or optical signals that carry digital data streams. Thesignals through the various networks and the signals on network link 520and through communication interface 518, which carry the digital data toand from computer system 500, are example forms of transmission media.

Computer system 500 can send messages and receive data, includingprogram code, through the network(s), network link 520 and communicationinterface 518. In the Internet example, a server 650 might transmit arequested code for an application program through Internet 528, ISP 526,local network 522 and communication interface 518.

The received code may be executed by processor 504 as it is received,and/or stored in storage device 510, or other non-volatile storage forlater execution.

In the foregoing specification, embodiments of the invention have beendescribed with reference to numerous specific details that may vary fromimplementation to implementation. The specification and drawings are,accordingly, to be regarded in an illustrative rather than a restrictivesense. The sole and exclusive indicator of the scope of the invention,and what is intended by the applicants to be the scope of the invention,is the literal and equivalent scope of the set of claims that issue fromthis application, in the specific form in which such claims issue,including any subsequent correction.

What is claimed is:
 1. A method comprising: receiving a request forfirst content to present on a computing device, wherein the requestincludes an identifier; in response to receiving the request:determining whether user data that is associated with the identifier isstored in cache storage; in response to determining that no user datathat is associated with the identifier is stored in the cache storage:retrieving, based on the identifier, first user data from a first datastore of a plurality of data stores; determining response time dataassociated with a second data store of the plurality of data stores;determining, based on the response time data, to not wait to retrieve,from the second data store, second user data that is associated with theidentifier and that is stored in the second data store; determining,based on the first user data, second content to send to the computingdevice; and sending, to the computing device, the first content and thesecond content; wherein the method is performed by one or more computingdevices.
 2. The method of claim 1, wherein the determining the secondcontent occurs in response to receiving the request and after retrievingfirst user data from the first data store.
 3. The method of claim 1,further comprising: in response to receiving the request and beforeretrieving first user data from the first data store, determining thatthe first data store and the second data store from the plurality ofdata stores include data that is associated with the identifier.
 4. Themethod of claim 1, wherein the request is a first request, and themethod further comprises, after determining to not wait to retrieve thesecond user data: retrieving the second user data from the second datastore; combining the second user data with the first user data togenerate combined user data; storing the combined user data in the cachestorage; after storing the combined user data in cache storage and afterdetermining the second content to send to the computing device,receiving a second request for third content to present on a secondcomputing device; and in response to receiving the second request:retrieving the combined user data from the cache storage; anddetermining, based on the combined user data, fourth content to send tothe second computing device.
 5. The method of claim 4, wherein theidentifier is a first identifier, the method further comprising, priorto combining the first user data with the second user data: determiningthat the first identifier is associated with a second identifier that isdifferent than the first identifier; and retrieving, based on the secondidentifier, particular user data from a particular data store of theplurality of data stores; wherein the combined user data comprises atleast a portion of the particular user data.
 6. The method of claim 1,wherein the identifier included with the request comprises a networkingprofile identifier.
 7. The method of claim 1, wherein the request is afirst request, the method further comprising: receiving a second requestfor third content to present on a second computing device, wherein thesecond request includes a second identifier; and in response toreceiving the second request: determining whether user data that isassociated with the second identifier is stored in the cache storage; inresponse to determining that particular user data that is associatedwith the second identifier is stored in the cache storage, determiningwhether the particular user data in the cache storage is classified asstale; and in response to determining that the particular user data inthe cache storage is classified as stale: determining, based on theparticular user data, fourth content to send the second computingdevice; and after determining that the particular user data isclassified as stale: retrieving, based on the second identifier, firstparticular user data from the first data store and second particularuser data from the second data store; combining the second particularuser data with the first particular user data to generate combinedparticular user data; and storing the combined particular user data inthe cache storage.
 8. The method of claim 1, wherein determining to notwait to retrieve second user data comprises determining that, based onthe second user data being stored at the second data store, retrievingthe second user data would exceed a predetermined time to respond to therequest.
 9. The method of claim 8, wherein the determining thatretrieving the second user data would exceed the predetermined time isbased on historical data of one or more response times of the seconddata store.
 10. The method of claim 1, wherein determining to not waitto retrieve the second user data from the second data store comprises:sending, to the second data store, a data request for data that isassociated with the identifier; and determining that a threshold periodof time has elapsed since the data request was sent to the second datastore and that no response to the data request has yet been receivedfrom the second data store.
 11. The method of claim 1, wherein theidentifier is at least one of a social network member identifier, ahashed email address, a browser identifier, a device identifier, or athird-party identifier established by a third party that is differentthan a party that receives the request.
 12. The method of claim 1,wherein the first data store stores a first type of data that is notfound in the second data store and the second data store stores a secondtype of data that is not found in the first data store.
 13. The methodof claim 12, wherein: the first type of data includes profile data aboutmultiple users, which provide the profile data; and the second type ofdata includes non-profile data that is derived based on behavior datathat indicates online activities in which a subset of the multiple usersparticipate.
 14. The method of claim 1, wherein: a third data store, inthe plurality of data stores, stores user data from a third party thatis different than a party that receives the request.
 15. The method ofclaim 1, wherein the first data store comprises a data store created andmaintained by a social network.
 16. A system comprising: a cachestorage; one or more processors; one or more storage media storinginstructions which, when executed by the one or more processors, cause:receiving a request for first content to present on a computing device,wherein the request includes an identifier; in response to receiving therequest: determining whether user data that is associated with theidentifier is stored in cache storage; in response to determining thatno user data that is associated with the identifier is stored in thecache storage: retrieving, based on the identifier, first user data froma first data store of a plurality of data stores; determining responsetime data associated with a second data store of the plurality of datastores; determining, based on the response time data, to not wait toretrieve, from the second data store, second user data that isassociated with the identifier and that is stored in the second datastore; determining, based on the first user data, second content to sendto the computing device; and sending, to the computing device, the firstcontent and the second content.
 17. The system of claim 16, wherein theinstructions, when executed by the one or more processors, furthercause: in response to receiving the request and after retrieving firstuser data from the first data store, selecting, based on the first userdata, the second content to send to the computing device.
 18. The systemof claim 16, wherein the instructions, when executed by the one or moreprocessors, further cause: in response to receiving the request andbefore retrieving first user data from the first data store, determiningthat the first data store and the second data store from the pluralityof data stores include data that is associated with the identifier. 19.One or more storage media storing instructions which, when executed byone or more processors, cause: receiving a request for first content topresent on a computing device, wherein the request includes anidentifier; in response to receiving the request: determining whetheruser data that is associated with the identifier is stored in cachestorage; in response to determining that no user data that is associatedwith the identifier is stored in the cache storage: retrieving, based onthe identifier, first user data from a first data store of a pluralityof data stores; determining response time data associated with a seconddata store of the plurality of data stores; determining, based on theresponse time data, to not wait to retrieve, from the second data store,second user data that is associated with the identifier and that isstored in the second data store; determining, based on the first userdata, second content to send to the computing device; and sending, tothe computing device, the first content and the second content.
 20. Theone or more storage media of claim 19, wherein the instructions, whenexecuted by the one or more processors, further cause: retrieving thesecond user data from the second data store; combining the second userdata with the first user data to generate combined user data; storingthe combined user data in the cache storage; after storing the combineduser data in cache storage and after determining second content to sendto the computing device, receiving a second request for third content topresent on a second computing device; and in response to receiving thesecond request: retrieving the combined user data from the cachestorage; and determining, based on the combined user data, fourthcontent to send to the second computing device.